关于初2下册的数学分式通分的问题?拜托各位了 3Q1:x-y与2y^2/x+y 2:2/9-3a,a-1/a^2-9与a/a^2-6a+9
1.(x-y)/(x+y) 2y^2(x-y)/(x+y) 2.-2(a-3)(a+3)/3(a-3)^2*(a+3) (a-1)(a-3)(a+3)/(a-3)^2*(a+3) a(a+3)/(a-3)^2*(a+3)
1:x-y与2y^2/(x+y) ;公分母为(x+y); 通分后分别为:(x-y)(x+y)/(x+y);2y^2/(x+y); 2:2/(9-3a)=2/{3(3-a)}=-2/{3(a-3)}; (a-1)/(a^2-9)=(a-1)/{(a-3)(a+3)}; a/(a^2-6a+9)=a/(a-3)^2; 公分母为:3(a-3)^2(a+3); 通分后各式为:-2(a-3)(a+3)/{3...